Synchronized beamline at FLASH2 based on high-order harmonic generation for two-color dynamics studies.

We present the design, integration, and operation of the novel vacuum ultraviolet (VUV) beamline installed at the free-electron laser (FEL) FLASH. The VUV source is based on high-order harmonic generation (HHG) in gas and is driven by an optical laser system synchronized with the timing structure of the FEL. Ultrashort pulses in the spectral range from 10 to 40 eV are coupled with the FEL in the beamline FL26, which features a reaction microscope (REMI) permanent endstation for time-resolved studies of ultrafast dynamics in atomic and molecular targets. The connection of the high-pressure gas HHG source to the ultra-high vacuum FEL beamline requires a compact and reliable system, able to encounter the challenging vacuum requirements and coupling conditions. First commissioning results show the successful operation of the beamline, reaching a VUV focused beam size of about 20 µm at the REMI endstation. Proof-of-principle photo-electron momentum measurements in argon indicate the source capabilities for future two-color pump-probe experiments.

Symmetry breakdown of electron emission in extreme ultraviolet photoionization of argon.

Short wavelength free-electron lasers (FELs), providing pulses of ultrahigh photon intensity, have revolutionized spectroscopy on ionic targets. Their exceptional photon flux enables multiple photon absorptions within a single femtosecond pulse, which in turn allows for deep insights into the photoionization process itself as well as into evolving ionic states of a target. Here we employ ultraintense pulses from the FEL FERMI to spectroscopically investigate the sequential emission of electrons from gaseous, atomic argon in the neutral as well as the ionic ground state. A pronounced forward-backward symmetry breaking of the angularly resolved emission patterns with respect to the light propagation direction is experimentally observed and theoretically explained for the region of the Cooper minimum, where the asymmetry of electron emission is strongly enhanced. These findings aim to originate a better understanding of the fundamentals of photon momentum transfer in ionic matter.

Angular momentum sensitive two-center interference.

In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

Feedback-controlled forcing of meandering spiral waves in an open gel reactor

The control of spiral wave dynamics has attracted much interest recently. Besides external forcing at a fixed frequency, feedback-controlled forcing has been studied. One of the simplest feedback schemes is to measure the activity level at a particular point of the medium continuously and to apply a spatially uniform pulsatory modulation if a certain threshold is reached at the detector. We have realized this feedback loop using an open gel reactor for the light-sensitive Belousov-Zhabotinskii medium. This allows us to maintain stationary nonequilibrium conditions over several hundred rotation periods of the unperturbed spiral wave. By varying the distance between the detector and the spiral tip, we find different stable branches of the resonance attractor for the same medium. We confirm the constant spacing between neighboring stable branches as predicted by Zykov and Karma and measure the dependence of the resonance drift on the forcing amplitude.

Photophysical properties and photodynamic activity in vivo of some tetrapyrroles.

Some of the photophysical properties (stationary absorbance and fluorescence, fluorescence decay times and singlet oxygen quantum yields) of pheophorbide a, metal-free, ClAl-, Cu- and Mg-t-butyl-substituted phthalocyanines, metal-free, ClAl- and Cu-t-butyl-substituted naphthalocyanines and of a number of tetraphenylporphyrins (5,10,15,20-tetraphenylporphyrin, 5,10,15,20-tetra(m-hydroxyphenyl)porphyrin, 5,10,15,20-tetra(p-hydroxyphenyl)porphyrin) have been studied in comparison with hematoporphyrin IX in order to select potent photosensitizers for the photodynamic treatment of cancer. The photodynamic activity of these compounds was investigated using Lewis lung carcinoma in mice. As a consequence of the photophysical parameters (relatively short singlet state lifetimes, and high singlet oxygen quantum yields) the photodynamic activities of pheophorbide a, t-butyl-substituted ClAl-phthalocyanine and ClAl-naphthalocyanine were selected for study in greater detail. Under the conditions employed in the present study, pheophorbide a was found to be the most effective sensitizer, as judged from its strong absorption at the excitation wavelength as compared with the hematoporphyrin derivative and greater singlet oxygen quantum yield relative to the phthalocyanines and naphthalocyanines. The photodynamic activity was observed to be strongly dependent on the photophysical parameters of the compounds. The primary mechanism underlying the photodynamic activity of these sensitizers probably consists of energy transfer from the lowest triplet state of the dyes to molecular oxygen, resulting in the formation of singlet oxygen (type II of photosensitization).

The propagation of avian viruses in a continuous cell line (QT35) of Japanese quail origin.

Seven of nine avian virus families tested (Birnaviridae, Coronaviridae, Herpesviridae, Paramyxoviridae, Poxviridae, Reoviridae, and Retroviridae) were found to replicate in a quail fibroblast cell line, designated QT35, resulting in a cytopathic effect (CPE) visible with the naked eye or by low-power microscopy. In comparison, only one (Paramyxoviridae) of seven mammalian virus families tested produced an observable CPE. Cytopathic changes induced by examined viruses were round cell, syncytial, and focus formation. Trypsin did not promote cytopathic changes by selected CPE-negative avian and mammalian viruses in QT35 cells. Several avian viruses (infectious bursal disease virus, Newcastle disease virus, Canary pox virus, and reovirus) formed plaques under agar. Avian reovirus and infectious bursal disease virus produced similar titers in chicken embryo fibroblast (CEF) and QT35 cell cultures. Chicken-egg-yolk neutralizing-antibody titers to IBDV were comparable in CEF and QT35 cell-culture systems.

A case of acute pulmonary edema, splenomegaly, and ascites in guinea fowl.

Acute pulmonary edema, splenomegaly, and ascites were observed in a disease outbreak in adult white and pearl guinea fowl. The clinical history and gross and microscopic lesions resembled those described for marble spleen disease of pheasants and avian adenovirus group II splenomegaly of chickens. A small number of intranuclear inclusion bodies were found in liver, spleen, and lung sections of affected guinea fowl. Attempts to isolate virus and serological tests to detect the presence of viral antigens were unsuccessful. Adult female pearl guinea fowl experimentally exposed to pheasant and turkey isolates of type II avian adenoviruses developed gross and microscopic lesions similar to those seen in the field outbreak. The pheasant isolate was the more virulent. Intranuclear inclusion bodies were observed in liver, spleen, and lung sections of pearl guinea fowl inoculated with either of the virus isolates, and direct immunofluorescent examination revealed viral antigen in the spleen and lung.

An infectious bronchitis virus isolated from chickens experiencing a urolithiasis outbreak. I. In vitro characterization studies.

An infectious bronchitis virus (IBV) strain isolated from commercial layers experiencing urolithiasis was 50-100 nm in size and possessed widely spaced, club-shaped surface projections. It was sensitive to lipid solvents and exhibited responses characteristic of IBV when exposed to heat, divalent cations, and trypsin. Reciprocal virus-neutralization tests demonstrated it to be closely related to Gray, JMK, Delaware 2868, and Delaware 2897 strains of IBV.

An outbreak of avian urolithiasis on a large commercial egg farm.

A significant outbreak of avian urolithiasis was observed on a large commercial egg farm. From the initial outbreak site (a single laying house), the incidence of urolithiasis slowly spread in the ensuing months to numerous other laying houses. Increasing mortality associated with urolithiasis commenced during late growout to early lay and then leveled off when egg production peaked. At the height of the outbreak, mortality was typically 0.5% per week; 75% of this mortality was due to urolithiasis. The clinical and pathologic features of this condition are described. Both infectious bronchitis virus (IBV) and fowl adenoviruses were isolated from organ homogenates of sampled birds. A clone of the IBV strain was found to induce nephritis in specific-pathogen-free white leghorns.

[Occult fractures in infants and children]. / Maskierte Frakturen im Säuglings- und Kindesalter.

Examples of occult skeletal lesions such as greenstick and depressed fractures, bends in bones and lesions of the non-ossified epiphyses in babies and young children are given and the possibilities of diagnosis are demonstrated. If there are corresponding clinical symptoms a special admission for follow up examination should follow after 10-14 days in order to observe around a discrete lesion. The value of bone imaging in early lesions is emphasized.

Cyst-like defects following fractures in children.

Cyst-like cortical defects appearing a few weeks after a greenstick fracture in the undamaged part of the radius were observed in 9 children. Five children showed multiple lesions. These radiolucent cyst-like defects 2.4 to 48 mm proximal to the fracture line seemed to be situated within the zone of periosteal reaction. The diameter of the cyst-like defects varied from 3 to 7 mm, usually they were rounded or slightly oval. Fracture healing was unaffected. In three of the patients the lesions had disappeared on to three years later. We are convinced that these benign lesions are resorption cysts within the excessive periosteal reaction and related to the subperiosteal hematoma accompanying the greenstick fractures.

Multiple fractures in early infancy: report of two unusual cases.

Two cases of multiple fractures, one in a newborn with an unclassified bone dysplasia, another in an infant with recurrent fits of unknown etiology are reported. The second case is the youngest in the literature with bilateral slipped capital femoral epiphyses and bilateral femoral neck fractures, secondary to stress injury.

[Congenital cystic adenomatoid lung malformation of newborn (author's transl)]. / Die angeborene zystisch adenomatoide Lungenfehlbildung des Neugeborenen.

The congenital cystic adenomatoid malformation (CCAM) of the newborn is a particular form among the cystic disorders of the lung. The clinical findings, illustrated by four cases, and especially the roentgenographic symptoms are typical. Different radiologic examinations, including the computer tomography, are discussed. The differential diagnosis of the disease is various, and therefore a correct and on time diagnosis is necessary, because the prognosis of the patient depends on an adequate therapy.

[On the indication of cesarean section in moribunda (author's transl)]. / Zur Indikationsstellung der Sectio caesarea in moribunda.

A case of cesarean section in moribunda is reported. The patient died on spontaneous subarachnoid and cerebral hemorrhage due to an angioma arteriovenosum aneurysmaticum of the right arteria cerebri media. Medical problems and the indication for a section in such cases are discussed. In non letal maternal diseases a section in moribunda should be separated from a cesarean section in extremis.

Splinter haemorrhages, pitting, and other findings in fingernails of healthy adults.

Splinter haemorrhages, pitting, transverse grooving, ridging, and flaking occur often in the fingernails of the healthy. While they may occur more often in certain diseases they have little diagnostic value in the absence of proper methods of measurement and examination and without a range of normal values for the sexes and age groups.